IEEE C37.121-2012 pdf download IEEE Guide for Switchgear—Unit Substation—Requirements
3. Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE SiandardsDictionary: Glossary of Terms & Definitions should be referenced for terms not defined in this clause.
articulated unit substation: A unit substation in which the incoming, transforming, and outgoing sectionsare manufactured as one or more subassemblies intended for connection in the field.
barrier: A partition within the enclosure and part of the contained equipment. used for the insulation orisolation ofelectric circuits or electric arcs.
conformance tests: Certain performance tests to demonstrate compliance with the applicable standardsThe test specimen is normally subjected to all planned routine tests prior to initiation of the conformancetest program.
NOTE–The conformance tests may, or may not, be Similar to certain design tests, Demonstration of margin(capabilities beyond the standards) is not required.
design tests: Tests perforied to determine the adequacy of the design of a particular type, style, or modelof any unit of equipment, or its component parts, to meet its assigned ratings and to operate satisfactorilyunder normal service conditions or under any specified conditions. Such tests may also be used todemonstrate compliance with applicable standards of the industry
NOTE 1–Design tests are performed on representative apparatus or prototypes to verify the validity of design analysisand calculation methods, and to substantiate the ratings assigned to all other apparatus of basically similar design.These tests are not intended to be performed on every design or during normal production. The applicable portion otthese design tests may also beused to cvaluate modifications of a previous design to assure that performance has notbeen adversely affected. Test data from previous similar designs may be used for current designs when appropriate.Once made, design tests need not be repeated unless the design is so changed as to modify performance.
NOTE 2–Design tests are sometimes called “type tests.”
enclosure: A surrounding case or housing used to provide a degree of protection to the enclosed conductorsor equipment, and to provide a degree of protection to personnel against incidentally contacting live parts.
high voltage: A general term that pertains to the primary voltage, or primary-voltage side, of a transformeror of a unit substation.
incoming section: Equipment that includes necessary mechanical and electrical connecting parts forcoordination in a unit substation on the high-voltage (or primary) side of a transformer section.
low voltage: A general term that pertains to the secondary voltage, or secondary-voltage side, of atransformer or of a unit substation.
other tests: Tests, so identified in individual product standards, that may be specified by the user inaddition to routine tests.(Examples: mpulse; insulation power factor; audible sound)
outgoing section: Equpment that includes necessary mechanical and electrical connecting parts for
coordination into a unit substation on the low-voltage (or secondary) side ofa transformer section.
primary unit substation: A unit substation in which the low-voltage section is rated above 1000 Y